Add section plugin: from scratch to publish runnable workflows

docs/sections/creating_plugins/from_scratch.md

@@ -0,0 +1,139 @@
+(plugins-from_scratch)=
+
+# Developing a workflow plugin and publish it from scratch - Example
+
+**Task:** From scratch, build an AiiDA plugin development environment. 
+By using AiiDA plugin cookie-cutter, create an AiiDA plugin consists of work chain based on the pwscf calculations plugins from [`aiida-quantumespresso`](https://github.com/aiidateam/aiida-quantumespresso). 
+Publishing the plugin to [AiiDA plugins registry](https://aiidateam.github.io/aiida-registry/).
+
+**Result:** Having an AiiDA plugin registried on AiiDA plugins registry which contain a workflow to run cohesive energy evaluation workflow based on chainning the processes from `aiida-quantumespresso`.
+
+**Time:** This should be easily doable in the available 1h.
+
+## Create a developing environment
+
+To start, we need a developing environment where the AiiDA and its related infrastructures (e.g. PostgreSQL and RabbitMQ) are installed and running.
+As shown in xx (aiidalab-launch), the aiidalab-launch will create and launch a docker container where the PostgreSQL, RabbitMQ and aiida-core are ready to use. 
+All you need to do are:
+
+1. Install Docker on your workstation or laptop.
+2. Install AiiDAlab launch with pipx or directly with pip (pip install aiidalab-launch)
+3. Start AiiDAlab with 
+
+```
+aiidalab-launch start
+```
+4. Follow the instructions on screen to open AiiDAlab in the browser.
+
+In the browser it will connect to the Jupyter interface of AiiDAlab which consist of a terminal you can run all the AiiDA verdi commands, and a filesystem interface where you can manipulate with files.
+
+The vscode support to configure and [developing project inside a container](https://code.visualstudio.com/docs/remote/containers).
+This enable all the functionalities of vscode as developing in the localhost. 
+
+First open the vscode and [attach to the running AiiDAlab container](https://code.visualstudio.com/docs/remote/attach-container) you just launched.
+
+[image..]
+
+The container mounted in vscode will have `root` as the default user, you need to change the user to `aiida` in attached container configuration files, either can be the configure file on image-level (default) or the configuration file tied to a container name (if you have multiple containers from the same image.). 
+Set the value `remoteUser` to `aiida` as:
+
+```json
+{
+    "remoteUser": "aiida",
+}
+```
+
+Reopen the container in vscode to load the new configuration.
+Now if you [open the integrated terminal of vscode](https://code.visualstudio.com/docs/terminal/basics#:~:text=To%20open%20the%20terminal%3A,the%20View%3A%20Toggle%20Terminal%20command.) from inside the attached container in your workspace, you'll find that you are the user `aiida`. 
+It not only change the user to `aiida` in vscode but will map the GitHub credential from your localhost so you don't need to reset the GitHub configuration in vscode.
+
+### [Option: intall the vscode extensions for vscode container environment]
+
+We recommend to install `Python Extension Pack` extension pack for the python developing and `Better TOML` for the syntax highlight for the package setup `toml` file. 
+
+## Create a plugin package from cookie-cutter.
+
+In the vscode terminal run:
+
+```
+cookiecutter https://github.com/aiidateam/aiida-plugin-cutter.git
+```
+
+Just follow the instructions and answer the prompted questions.
+This will produce the files and folder structure for your plugin, already adjusted for the name of your plugin.
+Please check [aiida-plugin-cutter](https://github.com/aiidateam/aiida-plugin-cutter) for more details of how to use the cutter.
+You will want to install your plugin in `editable` mode, so that changes to the source code of your plugin are immediately visible to other packages:
+
+```
+cd aiida_<name>
+pip install -e .  # install in editable mode
+```
+
+Open the folder of the package you just create to start working the project.
+You are now ready to start development!
+If you have `Python Extension Pack` installed as shown in .., you can [select python interpreter for your project](https://code.visualstudio.com/docs/python/environments#_select-and-activate-an-environment) to load the interpreter and have all modules of dependencies tractable by the vscode IDE.
+It will allow you to see that the modules are synax highlight and able to go to the definition of the modules and functions to [quick navigate the code](https://code.visualstudio.com/docs/editor/editingevolved#_go-to-definition), which accelarate your development a lot.
+
+
+## Write workflow to calculate cohesive energy using process from aiida-quantumespresso
+
+### Install Quantum ESPRESSO and aiida-quantumespresso in container
+
+Our target plugin will container a workflow which running Quantum Espresso `pw.x` from using the `PwBaseWorkChain` of `aiida-quantumespresso`.
+The Quantum Espresso in this purpose is mostly for developing and testing purpose, it can be easily installed from conda forge:
+
+```
+$ conda create --yes --override-channels --channel conda-forge --prefix ~/.conda/envs/quantum-espresso-7.0-custom qe=7.0
+```
+
+The excutable `pw.x` can be then found from `~/.conda/envs/quantum-espresso-7.0-custom/bin/pw.x`.
+Typically, to running a MPI `pw.x` calculation just in the working directory which pwscf inputs located, run:
+
+```
+$ ~/.conda/envs/quantum-espresso-7.0-custom/bin/mpirun -np 2 ~/.conda/envs/quantum-espresso-7.0-custom/bin/pw.x < pw.inp > pw.out
+```
+
+or activate the correspond conda environment first and run:
+
+```
+$ conda activate quantum-espresso-7.0-custom
+$ mpirun -np 2 pw.x
+```
+
+Install the `aiida-quantumespresso` by just running:
+
+```
+$ pip install aiida-quantumespresso
+```
+
+and SSSP pseudopotential library by:
+
+```
+$ aiida-pseudo install sssp
+```
+
+You can then configure an aiida code for the `pw.x`:
+
+```
+$ verdi code setup --non-interactive --label pw-7.0 --description "pw.x (7.0)" --input-plugin quantumespresso.pw --computer localhost --prepend-text "conda activate quantum-espresso-7.0-custom" --remote-abs-path "/home/aiida/.conda/envs/quantum-espresso-7.0-custom/bin/pw.x"
+```
+
+### Writing workflow
+
+Ref to 'writing_workflows-workchain' to create a EOS workflow.
+
+Download `utils.py` and create `rescale.py` with the content from section in to `aiida_wf_demo`
+
+Create a 'workflows.py' with the content of the WorkChain 'EquationOfState'.
+
+Import the module:
+
+```python
+from aiida_wf_demo.rescale import rescale
+from aiida_wf_demo.utils import generate_scf_input_params
+```
+
+### Adapt the package setup
+
+- Registry the entry points.
+- Specify the dependencies.

docs/sections/creating_plugins/index.rst

@@ -7,7 +7,32 @@ Creating plugins
 
     If you haven't done so already, please **first** watch the `introduction to the AiiDA plugin system <https://www.youtube.com/watch?v=bjTUnHXZ6oY&list=PL19kfLn4sO_-e_A9lVYb_NBNcwoVvUP6V>`_ (~20 minutes).
 
-    For this session, pick one of two options depending on your interests and experience:
+    For this session, pick one of three options depending on your interests and experience:
+
+.. panels::
+    :header: panel-header-text
+    :body: bg-light
+    :footer: bg-light border-0
+
+    ------
+    :column: col-lg-12
+
+    .. link-button:: from_scratch
+        :type: ref
+        :text: A - Developing a workflow plugin and publish it from scratch - Example
+        :classes: btn-light text-left stretched-link font-weight-bold
+    ^^^^^^^^^^^^
+
+    **Goal:** You would like to learn how to quickly build up a developing environment and having a minimal usable workflow published.
+
+    +++++++++++++
+    .. list-table::
+        :widths: 50 50
+        :class: footer-table
+        :header-rows: 0
+
+        * - |time| 1h
+          - |aiida| :aiida-blue:`Basic`
 
 .. panels::
     :header: panel-header-text